PSV - Recycle compressor circuit

[ginza]

Hello,

I need to specify the pressure relief valve in the reaction loop of a HDT unit.
The process (quite typical i think) is the following:

1) Make-up compressor
2) Recycle compressor
3) HC Feed pump.
4) The mixed streams from the above equipment flow through the Feed/Effluent exchangers, the Heater, Reactors, Feed/Effluent exchangers again, aircooler and reach the high pressure separator, where is located the pressure valve that i need to specify.
I hope this brief description is enough to understand the system.

I have done the calculations for the cases: aircooler failure, blocked outlets, fire.
What do i need to consider for HC Feed pump failure? And for Total Power electrical failure?
Any idea?

Thanks a lot,
Ginza.

 

[Montemayor]

ginza:

Why is it that you leave out the most important basic data of any compressor relief scenario: What type of compressor are you dealing with?

I'll guess it's a centrifugal, but I could be wrong. It basically makes all the difference in the world. The same applies for the "HC" pump - whatever that is.

When you try to communicate in acronyms you only cause confusion and erroneous concepts; it's bad communications - especially among experienced and knowledgeable engineers. A pressure relief scenario is serious business and shouldn't be taken lightly by using jargon or acronyms to describe the engineering configuration. The physical type of compressor and pump impact on the pressure scenario in the most important manner.

With the correct information, we can make accurate analysis.

Art Montemayor
Spring, TX

 

[ginza]

Montemayor,

both hydrocarbon feed pump and recycle compressor are centrifugal and with electrical motors.

If more information is needed, please let me know.

Thanks.

 

[Montemayor]

Ginza:

Thanks for your quick response. Now I can make a very strong point that I've always taught engineers under me in past years: When you have a centrifugal device, you've inherited an inherently pressure-limited device that you can exploit with sound, practical design - all related components should be design to withstand the top, dead-head pressure attainable by the machines. That way, there is no over-pressurization hazard. This formula is practical and employed by all experienced engineers when dealing with reasonable pressures that allow for the logic to work. It makes for a "fail-safe" situation when the centrifugal device reaches its maximum pressure.

If we can get the pressure levels regarding your process, you may be able to apply the logic.

Art Montemayor
Spring, TX